New house help please.

[oldasrocks]

Building my dream home and need help with HVAC, Read a couple threads in here and love this site.
House will be 42X40. with attached garage of another 30 ft long, so 42X70. Then 4 inches of closed cell foam with 4 inch split face block on the outside. Inside dividing walls 6 inch pour. Steel beams and steel roof with a R value insulation of 38. Nine windows 2X3, All steel insulated doors. Wall between house and garage are the same as the outside walls so heavily insulated. Fire wall to peak between house and garage insulated.

All duct work will be in the ceiling. As we are rural it will be propane heating. I want to include a Positive Air system. and this is where the confusion is. Will Positive Air system work with a propane furnace? I have all sealed windows planned. Confused on bathroom exhaust fans and stove exhaust fan.
One article I read in here said you do not even need fart fans in the bathrooms but how about humidity problems without exhaust fans? Read someplace there are fans with positive closure to not lose air pressure in the house. If the house is pressurized wouldn't just opening a vent result in exhaust without needing an actual exhaust fan?


I'm in way over my head here. So far the footers are poured and one section of the floor. Any advice would be helpful.

 

[mike93lx]

You have to use a separate system for the garage. Can't have it tied to the house system.

Are you diy'ing the install or using a pro?

 

[oldasrocks]

Yes there will be a separate air system in the garage. I intend to hire the work done for the HVAC system but need an education first. I have already ran into problems with subs in the concrete and plumbing areas. Luckily I know enough about both to fire them and hire someone else. In the process right now to tear out the rough in the plumber did and do it myself. Should have DIY'd it from the start but getting old and wanted to hire it done. Finally found a good man to do the flatwork. I built the footers for the concrete myself after advice from the engineer who built the local hospital. Flat work should be done in a few days. Floors are all insulated under them.

 

[Jackfre]

Minot or Miami? You will be looking for a sealed combustion furnace meaning direct vent, take outside air in one pipe, mix, burn and exhaust out the other. I would only use Panasonic fart fans and I also would not build without them. They have dampers in the exhaust to eliminate backflow.
As you are just planning this I would suggest that you put in a solar system and go mini-splits for H&C. I did it at our last home and ran the entire property, H/C & everything else at zero cost. Also for a heat only garage, install a Rinnai EX-22 or 38 if you go gas

 

[oldasrocks]

I don't believe in solar yet. You say zero cost? What will a new set of batteries cost for the system? A few around here have tried it but have not heard of any good results yet.

 

[mike93lx]

I don't believe in solar yet. You say zero cost? What will a new set of batteries cost for the system? A few around here have tried it but have not heard of any good results yet.

You don't believe in solar? What does that mean? It's a proven tech that is known to work

 

[chinboys]

It is steep learning curve to be used at this junction based on your background and experience.

I suggest you contact a specialist in HVAC-R who will design the systems you need by code. Spend the consultant fees and cry once. Otherwise, you will be crying all the time.

The Positive Air system being referenced is just an ERV... energy recovery ventilation system... to rid the polluted indoor air and to make up the air used by a kitchen hood exhaust and those other appliances (fart fan, furnace, fireplace, etc.) that has to be sized correctly.

 

[oldasrocks]

I'm sure you are correct. But out here in the backwoods where there are no codes it is hard to find someone knowledgeable. This is the main reason I am here to learn so I can recognize the con men.
Example: one concrete guy told me I don't need any steel or fiber in the concrete as cracks just happen. He is not pouring my concrete. I poured a cellar 15 yrs ago. 14 ft deep. To date no cracks.

 

[Sumboodie]

Is a 2x3 window code legal for a bedroom? May be something to look into. I had to go larger, I think mine are 3x5ft sliders, which gives about 7.5sq ft opening.
Also was a requirement on height from the floor.

Mention "no codes"... not exactly. The building code exists country wide, just some places don't enforce it.
Still a good to follow it, especially things that are for safety.

Also can bite you in the **** when you sell.

How about negative pressure in the garage?

 

[oldasrocks]

NO codes here in Rural Missouri. In town they have codes but not out here. These window are 2X3 on the inside but 2 X 18 at the opening. Walls 16 inches thick.( 8 inch pour, 4" insulation, and 4 inch block) Ever see the arrow slits on a castle? Windows won't open either. Since every wall in the house is concrete the only thing to burn is the clothes in the closet and it has a 90 minute fireproof door to close. Halon system in the kitchen. .Insulation is sandwiched between 2 concrete walls. It won't burn but will melt at 265 degrees. Windows will be higher as that side of the house is 4 ft underground. All wiring in conduit.

I don't plan on selling it. After I die I don't care. Back bedroom 12 X 18 with a walk in closet and bath in case we ever need live in help. Cheaper than a nursing home.

 

[ericm]

Code says you need openable windows large and low enough to get out in an emergency (they're often called "egress window"). I don't remember the exact size and height but it seems like a good idea so people don't get trapped and die in a house fire.

The place we're about to start building in Oregon will be heated and cooled with mini splits. The builder says that's all he does now. It's being built to Earth Advantage which is a kind of lightweight version of LEED that's used in the PNW. We'll be putting in solar too though electricity is much cheaper and more reliable there than in California. Unlike CA, Oregon has net metering for solar so it still makes financial sense.

I've stayed in places with mini splits and they work really well for heat and cooling. The shop and the ADU will get them too, so we'll have like seven of the things. They're cheaper to run than propane plus A/C.

 

[fitter30]

I'm sure you are correct. But out here in the backwoods where there are no codes it is hard to find someone knowledgeable. This is the main reason I am here to learn so I can recognize the con men.
Example: one concrete guy told me I don't need any steel or fiber in the concrete as cracks just happen. He is not pouring my concrete. I poured a cellar 15 yrs ago. 14 ft deep. To date no cracks.

There are companies that will run loads design systems on the internet. All they need is a set of prints. Did u just buy prints or working with a architect ( guess your not)they should know someone. There's also rebates federal, possibly state and electric. companies.

 

[thammel]

Just a thought. Consider a hybrid system for your house. By this I mean instead of just an AC, get a heat pump to work along with the propane fired gas furnace. The gas furnace will kick in when it's too cold for the heat pump to be effective.

 

[oldasrocks]

OK, What are "min splits?
NO I did not go to an architect. I did talk at length to a guy that built a local hospital for wall thickness to support what I want to do. Guess I have a bad habit of just building stuff. No formal education and mostly built out of steel over the years. Took me longer to make prints on AutoCad that to build a bridge. Threw away the prints and shop built it to fab on site later. Has been there for 25 yrs with no problems. This has nothing to do with a house though. I have built 3 over the yrs inc a Geodesic dome.

Trouble is I know nothing about a Positive Air System other that I was in a house once that had one and I liked the concept. House will be built like a Thermos bottle for heating and cooling. Heavy R factor and K factor. Retooled this old house we are living in now for the last 25 yrs. Problem is I have it sealed too tight and therefore we have a humidity problem in here. Cut the propane usage by 70 plus percent but causing other problems. That is why I am researching a PAS to use.

I do not care about Codes. No codes here in the countryside. I have seen some fire traps people live in around here that I would not spend a night in. Some built by so called professionals. There are doors accessible to the areas that will have sealed windows. Every door in the house will be 90 minute fire rated steel door with steel framework. Sorry I'm on a rant. As will probably be in a wheel chair in the future with my bad back I don't see a window as a means of escape.

 

[fitter30]

Live in a very rural area with no codes. Came from saint louis where id put union trades up against anyone in the country. Level ,plumb and square or don't put it in. ERV, HRV and heat wheels for fresh air. By not working with a mechanical engineer you have experienced what happens by using a guess. House so tight high rh wouldn't doubt that a Co reading might be high. Over 50% rh breeding ground for mold.

 

[oldasrocks]

So come on over for coffee fitter 30. We live just north of Lebanon. Practically neighbors.
I agree this old house is too tight. There is an overhead exhaust fan we do use. Doors get opened a lot with 3 dogs running in and out. You are right that maybe Co readings are high. I will get a gauge and check that.

You would poop your pants if you measured what the first concrete guy did. west footer is an inch below the east one. Screwed me up some as read ID's Measurement as OD. Over 2 1/2 inches out of square. So had to ignore where he had put in some rebar and start over with measurements for the interior footings. At least the outside footer is 30 inches wide so room to play with it. The engineer I had talked with recommended 24 inch footers so I went to 30 inch.

I agree in doing it right. Yrs ago I worked construction. Laying out a hog barn for pens in 580 ft X 80 ft I was less that 1/4 inch off. On each site I burned over 1 1/2 tons of rod.

 

[oldasrocks]

I looked into a heat pump and it is not practical here. Too hard to dig through the rocks to lay out the lines. Only works well down to 30 degrees. The way I did this old house we went from 600 gallons of propane a yr to 200 last yr. Filled a 500 gallon tank to 70% and have 30% left from last August. We cook with propane too.

 

[mike93lx]

I looked into a heat pump and it is not practical here. Too hard to dig through the rocks to lay out the lines. Only works well down to 30 degrees. The way I did this old house we went from 600 gallons of propane a yr to 200 last yr. Filled a 500 gallon tank to 70% and have 30% left from last August. We cook with propane too.

For a ground source heat pump or air source?

Air source is nothing beyond a normal a/c install and in a warm climate, should be a default

 

[Jackfre]

IN 2020 I added solar to my shop. It was a 30x34 with an 8/12 pitch. I used an outfit called Unbound Solar for sizing and bought the 24 collectors and associated hardware from them. They were excellent to deal with. I permitted it, installed all of it myself other than the electrical tie ins and for a 7.5kw system I was in for a total of $15.5k. I did Not have batteries. I did a Grid-tied system meaning I simply fed the power back into the grid and the utility paid me for it. I zeroed my electric bill and out here that is a real number. I figured a 4 yr pay-out on that system. Running mini-splits in the house, which also work, it was pretty sweet making my own power. Today I would look into a battery system or at least make accommodation to add one later, but as you are in the early stages do some research.

 

[oldasrocks]

Only way a ground source heat pump works around here is to dig two wells and put the pipe down there. Cost 20 grand.
I guess I am just an old codger that can't figure out this new fangled stuff. Our electric bill runs from $80 winter to $140 in the summer. With my luck I'd spend the 15 K plus more to have it installed and lighting would hit the house and fry everything.